适宜于光聚合过程应用的荧光探针研究

研究了两种探针化合物在安息香醚引发烯类单体光聚合反应中的应用，发现在光聚合反应中，不同的探针化合物有着不同的光谱响应特征和溶致变色行为，显然，这对探针的灵敏度会带来影响。实验结果表明：探针化合物在光聚合反应中能否应用，其光照稳定性起着关键作用，本工作推荐了一种适宜在烯类单体光聚合反应中应用的探针化合物。     

大面积水域浓度场测试方法及系统研究

针对大面积水域浓度场难以实现实时测量、测量精度不高等问题,采用了一种多通道荧光测试系统和方法。首先,基于单色光诱导荧光检测浓度(LIF)原理,使用探头获取离散点的浓度参数。然后,经总线或通信网络技术,将数百个测点连接起来。最后,通过数据总线或网络将采集的数据输送到中央测控计算机中,处理离散的数据后形成完整的浓度场。在恒定流浓度场中的试验结果表明,污染物测量相对误差均值不超过5%,单次测量相对误差最高值为8.33%,传感器线性度不超过5%,可检测的荧光素钠溶液浓度分辨率为0.001 ppm,系统测量稳定、精度较高。相较于其他浓度测量方法,该系统具有测量面积大、实时测量的优势,可为水污染防治等领域提供可靠的技术支撑。     

OptaDOS: A tool for obtaining density of states,core-level and optical spectra from electronic structure codes

We present OptaDOS, a program for calculating core-electron and low-loss electron energy loss spectra (EELS) and optical spectra along with total-, projected- and joint-density of electronic states (DOS) from single-particle eigenenergies and dipole transition coefficients. Energy-loss spectroscopy is an important tool for probing bonding within a material. Interpreting these spectra can be aided by first principles calculations. The spectra are generated from the eigenenergies through integration over the Brillouin zone. An important feature of this code is that this integration is performed using a choice of adaptive or linear extrapolation broadening methods which we show produces higher accuracy spectra than standard fixed-width Gaussian broadening. OptaDOS  may be straightforwardly interfaced to any electronic structure code. OptaDOS  is freely available under the GNU General Public licence from http://www.optados.org.     

Electrosyntheses and characterization of poly(5‐bromoindole) in boron trifluoride diethyl etherate

Poly(5‐bromoindole) (PBrI) films were synthesized electrochemically by direct oxidation of 5‐bromoindole in pure boron trifluoride diethyl etherate. The oxidation potential of 5‐bromoindole in this medium was measured to be only 0.97 V vs. saturated calomel electrode, which was lower than that determined in acetonitrile + 0.1 mol L^?1 Bu₄NBF₄ (1.08 V). PBrI films obtained from this medium showed good electrochemical behavior and good thermal stability. Structural studies showed that the polymerization of 5‐bromoindole ring occurred at 2,3 position. As‐formed PBrI films were thoroughly soluble in strong polar solvent dimethylsulfoxide and partly soluble in tetrahydrofuran. Fluorescent spectral studies indicated that PBrI was a good blue‐light emitter. The excitation and emission spectra of PBrI showed a significant shift to longer wavelength compared with that of the monomer, consistent with the greater extent of electron delocalization. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 539–547, 2006     

Swelling activation energy of κ‐carrageenan in its gel state: A fluorescence study

A steady‐state fluorescence technique was employed to study the swelling of κ‐carrageenan gels at various temperatures. Pyranine was used as a fluorescence probe. The fluorescence intensity of pyranine was measured during the insitu swelling process of κ‐carrageenan gels. The fluorescence intensity increased exponentially as the swelling time increased. The increase in the fluorescence intensity was modeled with the Li–Tanaka equation, from which the swelling time constants and cooperative diffusion coefficients were determined. The swelling time constants decreased and the cooperative diffusion coefficients increased as the swelling temperature was increased. The swelling activation energies were measured to be 47.05 kJ/mol. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Cuticular hydrocarbons ofReticulitermes virginicus (Banks) and their role as potential species- and caste-recognition cues

The cuticular hydrocarbon components of four castes ofReticulitermes virginicus (Banks) have been identified and quantitated. Components identified includen-alkanes; 2-, 3-, 11-, 13-, and 15-methyl-alkanes; 11,15-dimethylalkanes, (Z)-9-alkenes; (Z,Z)-7,9-dienes; and (E/Z)-6,9-dienes ranging in carbon number from C₂₁ to C₄₀. All caste forms ofR.virginicus contained the same components, but showed caste-specific proportions. Comparison of these hydrocarbons with those of the sympatric termiteR. flavipes (Kollar) suggest that cuticular hydrocarbons might serve as species- and caste-recognition cues. A bioassay was developed to test this species-recognition hypothesis, with the experimental results supporting the hypothesis.Isoptera: Rhinotermitidae.     

Cuticular lipids of the booklouse,Liposcelis bostrychophila: hydrocarbons,aldehydes, fatty acids,and fatty acid amides

The booklouse, Liposcelis bostrychophila, is an increasingly common pest of stored food products worldwide. We report here the cuticular lipid composition of this pest (the first report of the hydrocarbons of any member of the Order Psocoptera and the first report of fatty acid amides as cuticular components for any insect). No unsaturated hydrocarbons were present. A homologous series of n-alkanes (C₂₁–C₃₄), monomethyl alkanes (3-, 4-, 5-, 7-, 9-, 11-, 12-, 13- and 15-methyl-) with a carbon chain range of C₂₈–C₄₂, and dimethyl alkanes (3, 7-; 9, 13-; 11, 15-; 13, 17-; 9, 21-; 11, 19-; and 13, 21-); with a carbon number range of C₃₁–C₄₃ were identified. The relative abundances of these hydrocarbons were low, comprising approximately 0.0125% of total biomass. The amides were a homologous series (C₁₆–C₂₂ in chain length), with the major amide being stearoyl amide. In addition to the amides, free fatty acids (C_16:1, C_16:0, C_18:2, C_18:1, and C_18:0 in chain length) and three straight chain aldehydes (C₁₅, C₁₆, and C_17:1 in chain length) also occurred as cuticular components. These findings are discussed in terms of the chemical and physiological ecology of this species.     

Ce:Nd:ZnWO4激光晶体的生长及其光谱性能

采用提拉法生长出光学质量的Nd:ZnWO4,Ce:ZnWO4和Ce:Nd:ZnWO4晶体.通过X射线衍射仪对晶体样品的微观结构进行了分析.测试了晶体的吸收光谱、电感耦合等离子体原子发射光谱和荧光光谱.根据Judd-Ofelt理论计算出Nd:ZnWO4晶体中Nd3 的强度参数为:Ω2=6.820 2×10-20 cm2,Ω4=0.463 3×10-20 cm2,Ω6=0.443 5×10-20 cm2.研究了Ce3 和Nd3 之间的能量转移现象.结果表明:Nd3 在850 nm激发时产生上转换发射峰位于474 nm和572 nm处,分别对应于2G9/2,4K13/2到基态能级4I9/2跃迁,计算出该峰的自发辐射几率为1 360 s-1,荧光寿命为7.353×10-4 s,发射截面为0.905 9×10-23 cm2.     

日光照射对荧光增白剂VBL顺-反异构现象影响的研究

用紫外光谱和荧光光谱法对日光照射荧光增白剂VBL溶液进行了研究。结果表明、随日光照射时间的延长，VBL溶液在432nm处荧光强度下降；而在267nm处有所增强，低浓度溶液对日光照射更加敏感。1mg／1在避光时测得吸光度为0.449，而在日光照射15分钟后，其吸光度下降至0.141，证明日光照射使VBL溶液中的顺式异构体增加。     

Yb3+掺杂KLa(WO4)2激光晶体生长与光谱分析

采用提拉法生长出掺镱钨酸镧钾[Yb:KLa(WO4)2,Yb:KLW]晶体,测试了晶体的红外光谱和Raman光谱,对出现的振动模式进行了归属.从X射线衍射分析得到晶胞参数a=b=0.532 nm,c=1.189 nm.通过热重-差热分析得到晶体的熔点为1 119 ℃,在熔点以下没有相变.测试了晶体的吸收光谱和荧光光谱,计算了相应的光谱参数.结果表明:该晶体发射波长为1 021 nm,在931,981 nm附近有较强、较宽的吸收峰,适合用InGaAs半导体激光泵浦.